Thoughts of a (mad) computer scientist

Small Cell Bonanza

I find cellular infrastructure fascinating. As a technological society, we’ve made a tradeoff: we accept the presence of thousands of large, unsightly antennas perched on tall free-standing towers or on top of buildings in the midst of our communities in exchange for ubiquitous connectivity. To be fair, various communities (European cities and California come to mind) have come up with clever ways to ensure that this infrastructure is camouflaged through zoning restrictions, “tree towers” and the like. But, if you’re like me, then you can still find it.

Camouflaged “brick” antennas

The smartphone that you carry every day has a radio, just like the AM/FM radio in your car. It transmits and receives information from a transceiver that’s mounted somewhere high in the air. As cellular networks were being developed by Bell Labs in the 1960s and 1970s, the original designs used a single centralized antenna to serve a metropolitan area.

Depiction of central antenna covering the Chicago area from the AT&T Archives

Since then, cellular networks have been built on the principle of radio spectrum reuse. This now hilariously dated YouTube video from the AT&T Archives shows the difference in cellular network performance in Chicago before and after the implementation of AMPS, the first cellular network in the United States to use this technique.

Because the amount of radio spectrum allotted to cellular networks is limited, the principle of spectrum reuse is to utilize the same radio frequencies across many different antennas that are geographically dispersed. These distributed antennas transmit and receive at lower power levels than they would in the single, centralized antenna model shown above. By using this technique, the limited amount of radio spectrum can be used again and again across an area. That’s the general principle although there’s quite a bit of nuance involving radio frequency slicing and other techniques that prevent interference. Today, the leading wireless companies have deployed hundreds of thousands of cellular sites in this manner. These companies also work with the FCC to free up additional radio spectrum for use with their networks in order to raise capacity.

This now brings me to the topic at hand, the proliferation of small cells in cities around the US. While downtown Chicago has had a robust cellular network comprised of both macro-cells and small cells built out over many years, the buildout of small cells is now extending to other reaches of the city. The demand for high capacity data and voice capabilities makes sense in a more dense downtown area with commuters, large events, and more residents. However, it appears that the wireless carriers have reached a tipping point at which less dense areas of the city still require more capacity and have decided to initiate a wide-scale buildout of small cells. This is certainly a capital-intensive project but the carriers likely believe that next generation wireless or “5G” will require an even denser network of cells. I live in the Ravenswood area and have witnessed a huge amount of new small cells built out on light poles throughout the surrounding neighborhoods. I think this is a great thing for the city on the whole – we’ll have more reliable cellular signal and increased data capacity.

However, these small cells are just plain ugly! Compare the Verizon Wireless site on the left at Montrose and Ashland in Chicago to the site on the right in the Financial District in San Francisco.

Verizon small cell at Montrose and Ashland in Chicago

Small cell on light pole in Financial District in San Francisco

Both are situated on light poles but the San Francisco small cell is far less noticeable and appears to blend in with the pole itself. By contrast, the Verizon small cell has messy wiring and a bulky appearance.

Zoomed-in view: Verizon small cell at Montrose and Ashland in Chicago

To be fair, some of the other similar-looking Verizon small cells that I’ve observed around the city appear to have been installed with more care. I encourage Chicago city officials to enact stricter requirements on companies such as Crown Castle and Verizon Wireless to manage the appearance of small cells. It doesn’t have to be a tradeoff – we can have great coverage and keep our streets beautiful at the same time.